Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant's customer service levels, popularity trends, and more. The rankings reflect our opinion and should be a good starting point for shopping. As an Amazon Associate we may earn from qualifying purchases. We may receive a commission from purchases made through links on our site, which will help us continue to provide you with value.
Best Choice Hard-SF.com 
The Urania Project: Hard Science Fiction Best Value 
The Pull: A Hard Science Fiction Quest Beyond the Blind Spot (Cosmic Thresholds) 
Gravity's End: A Hard Sci-fi Novel in Space 
The Somatic Bridge: Gripping New Hard Sci-Fi Adventure. (Expansion Book 1) 
The Receiver: A Hard Sci-Fi First Contact Techno-Thriller 
Contact: Echoes in the Dark: Hard Science Fiction 
The Proxy War: A Hard Science Fiction Space Fleet Thriller (The Vanguard Calculus Book 2) Kaizen Publishing, LLC The Ambush: A Hard Military Space Fleet Thriller (The Vanguard Calculus Book 1) Terminator: Hard Science Fiction on a World That Never Turns (Cosmic Thresholds) Companionship: Long-form Science Fiction (A Brief History of the Universe) Side Story (A Brief History of the Universe: The Object: Hard Science Fiction Starquake: Hard Science Fiction at the Edge of Survival (Cosmic Thresholds) Keepsake: A Meridian Cut Science Fiction Story (Worlds Made Livable) Pygmalion Media Generations: A Science Fiction Mystery Thriller Hard-SF.com Mars Genesis: The Last Voyage: Hard Science Fiction Descartes' Shadow: A Metaphysical Hard Sci-fi AI Technothriller Edenroot Press Deep Space Expedition: A Hard Science Fiction Survival Mission (The Threshold Protocol Book 1) Hard-SF.com The Enceladus Mission: Hard Science Fiction (Ice Moon Book 1) Exodus Blue: A Posthumanism Hard Science Fiction Novel with AI and Mystery (The Colour of Blood Book 1) Amazon Original Stories Slow Time Between the Stars (The Far Reaches collection) TOR.com All Systems Red: The Murderbot Diaries Infinivox The Year's Top Hard Science Fiction Stories 10 Hard-SF.com The Luna Monolith: Hard Science Fiction (The Black Monolith Book 1) Uphill Downhill Press, LLC Wine Dark Deep: A Hard Science Fiction Space Opera - Book One: 1 Wilderness Five: Hard Science Fiction (Metamorphosis Book 1) Horizon Array: A Hard Science Fiction Survival Thriller A7L Thrilling Books Limited The Genesis Signal: Science Fiction Thriller The Wooden Pen Press Venusian Uprising - A Military Hard Science Fiction Epic (Aeon 14: The Sol Dissolution Book 1) Exemplar: Hard Science Fiction: The Autonomous Sequence (Book 1) Red Foundations Publishing Red Foundations: A Hard Science Fiction Epic (Red Foundations Universe Book 1) Hard-SF.com Mars Nation 1: Hard Science Fiction (Mars Trilogy) Das Echo: Hard Science Fiction (German Edition) Bastion (Toy Starship Book 4) Hard-SF.com The Torn Planet: Hard Science Fiction (The Marchenko Logfiles Book 1) The Darkness Between the Stars (First Contact) The Wanderer: Hard Science Fiction from the Darkest Ocean (Cosmic Thresholds) Hard-SF.com The Atacama Incident: Hard Science Fiction Hard-SF.com The Disturbance: Hard Science Fiction The Last Signal: A Hard Science Fiction Novel of First Contact and Lost Civilizations Futureword Publishing Blue SunRise: A Riveting Character-driven Hard Sci-fi Adventure (Blue Sun Space Opera Book 1) Futureword Publishing Blue SunRise: A Riveting Character-driven Hard Sci-fi Adventure (Blue Sun Space Opera Book 1) What Hard Times Hath Wrought: A Novelette (Vasicek Free Library Book 2) The Returner: A Post-Apocalyptic Military Science Fiction LitRPG (The Returner Book 1) The Mars Anomaly: Hard Science Fiction Final Contact (Two Complete Series) Five and a Quarter: Hard Science Fiction Defending Hope: An EMP Survival Story (Surviving The Shock Book 1) Hard-SF.com The Hole: Hard Science Fiction (Solar System Series Book 1) Edenroot Press The Quantum Drift: A Hard Science Fiction First Contact Thriller (The Threshold Protocol Book 2) Primordial Press Primordial Threat: A Hard Science Fiction Thriller (The Exodus Series Book 1) Hard-SF.com The Lost Planet: Hard Science Fiction (The Marchenko Logfiles Book 6) Nexus: A Science-Fiction Thriller Hard-SF.com The Hole: Hard Science Fiction (Solar System Series Book 1) Hard-SF.com The Luna Monolith 3: Hard Science Fiction (The Black Monolith) The Wooden Pen Press The Proteus Bridge - A Hard Science Fiction AI Adventure (Aeon 14: The Sentience Wars) The Shackleton Signal: Hard SF Thriller Primordial Press Primordial Threat: A Hard Science Fiction Thriller (The Exodus Series Book 1) Hard-SF.com The Rift: Hard Science Fiction (Solar System Series Book 3) Hard-SF.com The Krill Enigma: Hard Science Fiction Solan Publishing Journey Home (Standalone Sci-Fi Novels) Hard-SF.com The Triton Disaster: Hard Science Fiction (Solar System Series Book 4) Cosmic Entanglement Media The Foundry: A Hard-Science Fiction Space Opera (Book 1) Sci Fi Books Akashon Prime: A Hard Science Fiction Action Adventure (The Origin Series Book 2) Instrumental: Hard Science Fiction: The Autonomous Sequence (Book 2) Galactic Spacetime Publishing Time is not Enough: A Science Fiction Spy Thriller Pole-Zero Publishing The Cold Heavens: A Hard Science Fiction Adventure (The Olympian Order: Sky-Pirates of Venus Book 1) Hard-SF.com The Tiny Planet: Hard Science Fiction (The Marchenko Logfiles Book 5) Audible Solar Storm: Moon Base Delta, Book 1 Green Hill Publishing Homo Machina: A Post-Apocalyptic Hard Sci-fi Genetic Engineering Thriller Hard-SF.com The Shared Planet: Hard Science Fiction (The Marchenko Logfiles Book 3) Audible Solar Storm: Moon Base Delta, Book 1 Independent The Rings of Jupiter: Hard Science Fiction Hard-SF.com The Portal: Hard Science Fiction (Portal to Xibalbá Book 1) AS1 Hard-SF.com The Luna Monolith 2: Hard Science Fiction (The Black Monolith) Night Shade Books The Best of Greg Egan: 20 Stories of Hard Science Fiction Hard-SF.com The Frozen Planet: Hard Science Fiction (The Marchenko Logfiles Book 2) Endeavour (A Sleeping Gods Novel Book 1) scifi-thriller.com Reactor: Science Fiction Thriller Primordial Press Freedom's Last Gasp: A Hard Science Fiction Thriller (The Exodus Series Book 2) Threshold Geometry: An Adult Sapphic Hard Science Fiction Techno-Thriller of Orbital Mechanics, Corporate Governance, an Hard-SF.com Mars Nation 2: Hard Science Fiction (Mars Trilogy) Ryan Michael Upton TANKS ON A SPACESHIP: warfare action | hard sci fi engineering | military science fiction | tactical combat in space | s A. Nation Books FOUND (Hard Science Fiction with Deep space exploration - Domino Book 4): The Lost Ones Mirth Publishing Starship New Jersey Box Set: The Complete 10-Book SciFi Series Independently Published The Year's Top Hard Science Fiction Stories 2 Independently published The Disturbance 2: The Answer: Hard Science Fiction When the Pattern Breaks: A Sci-Fi Thriller (The Pattern Series Book 1) Hard-SF.com Proxima Rising: Hard Science Fiction (Proxima Trilogy Book 1) Hard-SF.com The Titan Probe: Hard Science Fiction (Ice Moon Book 2) 18% Off HarperVoyager The End of Eternity: A Classic Hard Science Fiction Adventure of Love and Time Travel Hard-SF.com Return to Enceladus: Hard Science Fiction (Ice Moon Book 4) Hard-SF.com Silent Sun: Hard Science Fiction (Solar System Series Book 2) Hard-SF.com Andromeda: The Arrival: Hard Science Fiction (The Long Journey Book 3) Audible The Prefect Rock and a Hard Place: An MM Alien Science Fiction Romance (The Little Ships Book 2) The Wooden Pen Press Storming the Norse Wind - A Hard Military Science Fiction Assault (Aeon 14: Origins of Destiny) Hard-SF.com The Portal 2: Hard Science Fiction (Portal to Xibalbá) Hard-SF.com Evolution: Hard Science Fiction (Proxima Logfiles Book 5) Hard-SF.com The Beacon: Hard Science Fiction (Solar System Series Book 7)